Bloodlines
Bloodlines is the twenty-third episode in the season four finale of . Synopsis The CSIs investigate when a casino employee is beaten and raped on her way home from work. The victim identifies her attacker, but the DNA evidence suggests that he is not the person responsible. Later, Grissom has to help out Sara Sidle who ends up on the other side of the law when found but not charged for a DUI. Plot A female pit boss at the Palms casino in Las Vegas leaves the casino and walks to her car before driving away. She's next seen bloody and partially clothed running through a wooded area and neighborhood before collapsing in the street. Some time later, she's been prepared by paramedics for transport to Desert Palms Hospital. CSI Supervisor Gil Grissom documents her injuries while Detective Jim Brass provides an update on neighborhood interviews. Grissom traces the victim's path through the neighborhood and wooded area to an abandoned car on the side of a road. The victim, Linley Parker, is processed at the hospital. CSI Sara Sidle asks CSI Catherine Willows to take her statement. She recounts her assault and rape clearly, then gives a physical description to a facial composite artist. At the lab, Sara's encouraged by Grissom to take some vacation time. She refuses, indicating she finds his recommendation hypocritical. Later, lab tech Greg Sanders approaches Grissom with DNA results from the rape kit that match it to the unsolved rape and murder of Emma Dobbins from a year earlier. He asks that he make a decision regarding his field status. Grissom tells him that as soon as he can find and train a replacement, he can move to fieldwork full-time. Using the facial composite and license plate information from the victim, Dr. Todd Coombs is identified as a suspect and brought in by Brass for questioning. Linley picks Coombs out of a police lineup and Grissom collects a DNA sample from him. Comparisons of Coombs' shoes and DNA to evidence from the crime scenes of both Linley Parker and Emma Dobbins results in no matches, however, although the seminal DNA indicates that the rapist is likely Coombs' brother. Coombs is released from custody and Catherine informs Linley, who remains sure of her lineup identification and fears retribution from Coombs. The CSIs workup a family tree for Coombs and speak with three of his brothers, collecting DNA from all of them. The fourth brother, Kevin Coombs, cannot be found. While at the lab, Catherine receives an urgent call from Linley that ends abruptly with sounds of a struggle and screams. Her car is found abandoned on Fremont Street with the window smashed and cell phone missing. The whereabouts of three Coombs brothers are confirmed, but Todd Coombs is said by his wife to be at the house company. Brass happens to drive by Coombs as he's vacuuming his car at a car wash and speaks to him briefly, but cannot search his vehicle without a warrant. CSIs track the GPS on Linley's phone to an empty lot on the edge of town. Her dead body is found in the same lot; she's been strangled. The next day, Detective Louis Vartann and Sara seek out the fifth Coombs brother, Kevin Coombs, at his trailer home. He answers the door with a shotgun and is taken into custody, where a DNA sample is compelled. Sara finds the missing car of the first victim, Emma Dobbins, on Kevin Coombs' property. CSIs Nick Stokes and Warrick Brown investigate the vacuum contents from the car wash and find a lapel pin from the Palms casino, where Linley Parker worked. None of the compelled DNA from the five Coombs brothers matches the seminal DNA from the murders or the blood DNA from the smashed window of Linley's car. However, Greg identifies a hair found on Linley's body as belonging to Todd Coombs. When Todd is brought back in for processing, Grissom observes a surgical scar and strange pale markings on his back. This leads him to the discovery that Todd Coombs has a condition called Tetragametic chimerism, in which the embryos of fraternal twins collapse into one. Grissom recalls a chimera statuette found and photographed in Coombs' home office. Grissom collects a blood sample from Coombs in his holding cell. After Grissom reveals that he knows Coombs' bone marrow donation to his brother failed, Coombs acknowledges he's aware of his condition: he has two completely different sets of DNA in his body. In the interrogation room, Coombs admits his guilt to Captain Brass while being video recorded. At the end of shift, Warrick, Sara, and Nick are seen walking down the strip. Warrick invites them to a meal, but they turn him down. Sara congratulates Nick on his almost-promotion, telling him he deserves it. Nick asks her if it was hard for her to say, and she agrees that it was. Later, Grissom receives a call in his office. An officer discloses that Sara has been pulled over for a DUI. While her BAC is technically over the legal limit, the limit had been lowered recently and the officer cuts her a break by not booking her. Grissom arrives at PD and tells Sara he'll take her home. Cast Main Cast * William Petersen as Gil Grissom * Marg Helgenberger as Catherine Willows * Gary Dourdan as Warrick Brown * George Eads as Nick Stokes * Jorja Fox as Sara Sidle * Eric Szmanda as Greg Sanders * Robert David Hall as Dr. Al Robbins * Paul Guilfoyle as Jim Brass Guest Cast * Alex Carter as Detective Louis Vartann * Joseph Patrick Kelly as Officer Metcalf * Ty Upshaw as Officer T. Brantley * Nina Siemaszko as Linley Parker * George Newbern as Dr. Todd Coombs * Lisa Sheridan as Crystal Coombs * Mark Kiely as Roger Coombs * Michael Reilly Burke as Bailey Coombs * Drew Pillsbury as Larry Coombs * Rachel Winfree as Psychic Patient Janet * Edmund Wyson as Officer Devine Major Events *Sara Sidle is pulled over for a DUI. Trivia * Dr. Todd Coombs has a condition called Tetragametic chimerism, which can cause a person to have two distinct sets of DNA in their body. For example, the seminal DNA in a person in a person with this condition could be different from the DNA in their saliva. * The actor playing Dr. Todd Coombs, George Newbern, also played the groom, Bryan MacKenzie, in the film, "Father of the Bride" and Charlie on ABC's "Scandal". See Also 423